(Revised Abstract) DESCRIPTION (provided by applicant): Studies in the last several years have shown that certain heat shock protein (hsp) family members, when purified from a tumor, elicit a strong immune response against the same tumor when used as a vaccine by virtue of their molecular chaperoning properties. Clinical application of this approach may be limited in some cases by the small amount of hsp present in an available surgical specimen. Moreover, it would be highly advantageous if such vaccines were available in the absence of surgery. Our recent efforts have concentrated on the cloning and characterization of two major hsps/stress proteins, hsp110 and grp170. Studies using recombinant hsp110 and grp170 with reporter proteins demonstrated that both were highly efficient molecular chaperones. This proposal continues the heat shock protein approach to vaccine based immunotherapy, but utilizes the natural chaperoning functions of these two novel hsps to produce more concentrated, targeted heat shock vaccine preparations. The First two aims of the project develop this approach by naturally complexing important tumor protein (Her-2/neu and gp100) and derived peptide antigens with hsp110 or grp170. Aim 3 then uses the peptide binding properties of these stress proteins as a novel approach for the identification of tumor peptide antigens. The subsequent use of these antigens, again in natural complex with hsp/grp, would provide yet an additional approach to vaccine development. Aim 1 is to study full-length tumor antigens, including Her-2/neu and gp100, which are bound to recombinant hspl10 (rhsp110) or grp170 (rgrp170) as vaccines; to evaluate their ability to elicit anti-tumor immune responses. Aim 2 is to examine the capacity of rhsp110 and rgrp170 to generate a peptide-specific cytotoxic T cell (CTL) response and specific tumor immunity when naturally coupled with CTL epitopes derived from Her-2/neu or gp100 tumor antigens. Lastly, Aim 3 is to sequence peptides isolated from tumor derived hsps as a method of identifying new tumor antigens and to investigate the effect of fever-range hyperthermia on the profile of peptides bound by these hsps. These studies will also interact with Projects 2 and 3 of this Program, which will investigate the interactions of heat shock vaccine therapy with fever-range thermal exposures. The Project will also rely heavily on all three cores. These studies determine the utility of targeted, natural chaperone complexes of recombinant heat shock protein with protein/peptide as cancer vaccines using two important tumor antigens and also define an approach by which new tumor antigens may be discovered. The results of these studies can be expected to present new strategies for the use of hspvaccine therapy that can be expected to have immediate clinical applications.